OMG! Don't waste your time and money on any of these fixes! There is only one way to do it right. Use a cut off wheel and cut the tank along the seam. Have it sand blasted then have a good welder put it back together. Then use a good tank sealer like Por-15.
I know this from many tractor...
Re: “Do not use a file” to dress down breaker points
If you're stuck out on the road use what eve you have. If you're in town don't be so darn cheap. Go buy a new set.